1. Field of the Invention
The present invention relates to a power supply technology, more particularly, to an AC-to-DC power supply apparatus and a power control structure and method thereof.
2. Description of the Related Art
An AC-to-DC converter is configured to convert an AC power (for example, city power) into a DC power, and supply the converted DC power to a load. Currently, the input power-factor and the harmonic content of the input current in the power supply have a variety of standard limitations. Accordingly, the configuration of the power-factor-correction (PFC) circuit in the AC-to-DC converter is generally the boost PFC converter.
The inductor in the boost PFC converter has a larger volume, and the effective cross section area (Ae) of the magnetic core of the inductor can be determined and calculated by the following expression (1):
                              A          e                =                                                            L                b                            ×                              i                                  Lb                  ⁢                                                                          ⁢                  _                  ⁢                                                                          ⁢                                      pk                    ⁢                    _                    ⁢                    max                                                                                      N              ×                              B                max                                              .                                    (        1        )            
In foregoing expression (1), Lb represents that the inductance of the inductor, iLb_pk_max represents that the maximum peak current of the inductor, N represents that the number of turns of the inductor, and Bmax represents that the maximum magnetic flux density.
It is clearly seen that, in foregoing expression (1), the volume of the inductor is closely related to the maximum peak current of the inductor (iLb_pk_max). Accordingly, the effective cross section area (Ae) of the magnetic core of the inductor increases as the maximum peak current (iLb_pk_max) of the inductor increases (the effective cross section area (Ae) of the magnetic core of the inductor is proportional to the maximum peak current (iLb_pk_max) of the inductor), but the power density of the AC-to-DC converter decreases as the volume of the inductor increases.